Seventeen months after Guardian Work exposed blacklisting in the construction industry, new laws outlawing the practice are set to come into force, and next week 23 of its alleged victims will start their court cases.

But for electricians such as Colin Trousdale it doesn't mean the scandal is over.

Officials from the Information Commissioner's Office (ICO) launched an investigation following Work's story. It led them to a shadowy group in Droitwich, Worcs, called The Consulting Association, run by 66-year-old Ian Kerr. There they found a database of some 3,200 names and invoices showing 44 construction firms, including some of the UK's biggest, had used its services.

Kerr was fined £5,000, The Consulting Association was closed and 14 of Kerr's clients given warning notices. Trousdale, 51, from Manchester, was interviewed for the original article as he claimed to be on a blacklist. Like the others interviewed, he now has copies of his file after the ICO investigation.

The six-page document opens in 2006, shortly before he launched an unsuccessful employment tribunal claim for being blacklisted. The last entry is October 2008.

However Trousdale says that since last December he's only had eight weeks' work. He has joined pickets at several construction sites in the north-west this year, highlighting what he sees as his continued blacklisting.

"I can only think that because I've raised health and safety concerns – and remember this is an industry in which 53 people died last year – I'm affecting profits and they don't want me doing that," he says.

According to the government, the likes of Trousdale should get better protection from new laws due before Christmas. The government had promised to outlaw blacklisting as part of the 1999 Employment Act but decided, after a review, there was no evidence it was an issue, so that part of the legislation was not enacted. After the exposure of The Consulting Association's activities, it carried out a hurried consultation on new regulations. These do not have to be debated and once published, can be signed into law by the business secretary, Lord Mandelson.

Professor Keith Ewing, from the Institute of Employment Rights, was commissioned by the builders' union Ucatt to study the proposed laws.

He has identified several loopholes, including the fact there is no right not to be blacklisted; that they do not make blacklisting a criminal offence and so put the onus on the victim to bring a case; and that the definition of "union activity" in relation to an individual is too tightly drawn, meaning information on other actions could legitimately be gathered.

"The regulations need to be stronger in order to eradicate blacklisting," says Alan Ritchie, general secretary of the Ucatt union, who has his own file. "For example, many of those blacklisted were due to health and safety issues, therefore the regulations should cover all activities associated with trade unions. The regulations should also stipulate that if a blacklist is discovered, all those on it should be informed and receive compensation."

MP John McDonnell wants a committee to consider the proposals to ensure they are properly worded and says this must be done soon or the result will be ineffective legislation. "The timing is critical," he says. "We need to scrutinise the wording but if this goes on after Christmas we might lose that chance in the run-up to an election."

Ewing studied a number of files as part of his research. "I was deeply offended at the amount of intimate and personal detail so meticulously gathered," he said. "At the same time, some files were hopelessly inconsistent."

Steve Kelly, 43, from Essex, was one of those who received a copy of his file. The 18-page document runs from 1998-2007 and includes minutes from a union branch meeting, along with allegations that Kelly was a "trouble maker", involved in "intimidating workers to join the union" and was even "writing abuse on the toilet walls".

"I was gobsmacked what they had on me," says Kelly. He is one of 238 people to have received their file, out of 1,872 who have contacted the ICO. Given this relatively small total, Ucatt has launched a poster campaign targeting 100,000 construction workers to encourage them to ask for theirs. It is not just Ucatt members affected though: the National Union of Rail, Maritime and Transport Workers and, in particular, public sector union Unite, also had members on the blacklist. One effect of the release of the files has been to question how far some union officials were involved in supplying details to The Consulting Association.

Another has been to strengthen the numerous legal actions being prepared. The traditional route is via an employment tribunal and this is the one union lawyers are pursuing. So many cases have been submitted that they are being lumped together and will be heard in Manchester. An initial case management discussion is due to take place on November 24, which will set a hearing date for the new year.

Dave Smith, 44, is one of those putting in a tribunal claim. His large file starts in 1999 and includes details on the car he drove, newspaper clippings and union correspondence.

He says: "The file specifically identifies incidents when I raised health and safety concerns. At no point is my competence as an engineer questioned. I believe the folder is prima facie evidence of deliberate and vindictive discrimination and victimisation." Smith has left the industry because he couldn't get work.

Other legal actions being considered by unions and individuals are through the Data Protection Act and the Human Rights Act. Lawyers say there are serious hurdles in the cases because of time limits and the proof required by the court. Meanwhile, solicitors at Guney, Clark and Ryan are compiling a class action. The firm has secured financial insurance and retained the barrister Hugh Tomlinson, a specialist on privacy and data protection.

For McDonnell, the blacklisting scandal requires a public inquiry so that those affected can properly air their grievances and those responsible can be cross-examined. "This is one of the worst ever cases of organised abuses of human rights in the UK," he says.

Many of the companies identified declined to comment other than to say they do not condone blacklisting.

This has already been a terrible year for a construction industry battered by the recession. In September the Office of Fair Trading (OFT) fined six recruitment firms for forming a cartel to supply labour. Separately the OFT fined 103 building companies a total of £129.5m for bid-rigging.

"These scandals have thrown into sharp focus that the UK construction industry is not fit for purpose in the way it operates," says Ucatt general secretary Ritchie. "That view is not just coming from the UK; many of the biggest blacklisters were multinational corporations, and their international boards have been shocked at what was happening. Already we are seeing personnel changes at a senior level and different approaches to work because of the scandal."

For Colin Trousdale, the best solution is a simple one. "I am not interested in the money, I am just interested in getting back to work," he says.

If you think that The Consulting Association held a file on you, ring the ICO on 08456 306060 or 01625 545745 between 9am-5pm, Monday to Friday and choose option one

From the files: The notes that scuppered the blacklisted workers' careers

The Consulting Agency's blacklist files were held on a card index, organised much like a local police intelligence system. They typically had a name, address and national insurance number, and some included material such as newspaper clippings, photographs, copies of union correspondence and reports from companies. The companies were identified by code numbers (the meanings of which have since been decoded). Those files that have been released have been redacted where they identify individuals other than the subject, to protect that person's privacy.

Mick Anderson, 40, married with three children, from Kerry, Ireland Submitted 250 job applications and took courses to keep his electrician training up to date but was out of work for 16 months. Anderson and his family moved to the Irish Republic three years ago because of the blacklist, but he has struggled to find work. His file includes this extract: "Information received by 3271/81 site manager at Heather T5 that the above is 'not recommended' by amicus."

George Fuller, 64, single, from London A bricklayer from Forest Gate, Fuller has a file that covers 1990 to 1998 but has been an active trade union member since the 1960s and was involved in several major disputes during the 1970s. "I think there must be another file," he says.

John Winstanley, 66, married with three children, five grandchildren and two great-grandchildren, from Liverpool This retired joiner's file was opened in 1975, when it was held by the Economic League, and ends in 2002. It has details on his heart bypass surgery in 2001. He is described as an "an old-style communist" in one entry. "I heard about the blacklist when I was an apprentice," he says. "You tried to beat it any way you could."

Darren O'Grady, 47, married with two children, from London O'Grady, an electrician, left the industry in 1990 after repeatedly failing to secure work and moved to America. Now back in the UK, he is a tutor with the TUC. "I am disappointed that the people who fingered me cannot be identified," he says.